Britney Spears says she watched Jamie Lynn's ABC News interview with 104-degree fever: 'She never had to work for anything'

Britney Spears has a lot to say about her sister Jamie Lynn's sit-down with ABC News.

One day after it aired, the "3" singer wrote about her feelings while watching it ... with a 104-degree fever and some other symptoms that sounded every bit as awful. She prefaced her note by saying that her security team had refused to get her medicine, citing a need to stay on her property. (She later reported that her fiancé, Sam Asghari, retrieved it.)

She then explained, "It was actually nice having a fever so high cause I had to surrender to not caring. Just couldn't give a f*** but my head hurt so bad."

Jamie Lynn gave the interview ahead of the Jan. 18 release of her new memoir, Things I Should Have Said, in which she addresses her public feud with her superstar sister. While Jamie Lynn said she's "only ever loved and supported" Britney, the singer herself has said in court, leading to the termination of the conservatorship she lived under for 13 years, and elsewhere that she has been badly wronged by her family.

There were a couple of things in particular that had bothered her about the interview. The first was "that my sister said was how my behavior was out of control. She was never around me much 15 years ago at that time …. so why are they even talking about that unless she wants to sell a book at my expense??? REALLY???"

Another was when Jamie Lynn was asked about Britney being upset that she had performed remixes of her songs, most likely at the 2017 Radio Disney Music Awards. (Jamie Lynn said she has talked to Britney about that, and that she didn't understand why she was upset, since it was a way of paying tribute to her.)

"I know it may seem like a silly thing to most people but I wrote a lot of my songs and my sister was the baby," Britney said. "She never had to work for anything. Everything was always given to her !!!!"

Later, Britney said, "I always was the bigger person. They all got to DO IT and PLAY ME and I always sat there and took it." She added, "So yes, they did ruin my dreams."

And Britney offered what seemed like a sarcastic good luck to her sister — "Hope your book does well, Jamie Lynn !!!!" — before vowing to sign off Instagram for "a while."

She didn't want to deal with the media anymore.

"The media, this business has always been extremely hateful to me," Britney said. "I've given enough … More than enough. I was never given back ever what I want."